ViraCore's technology uses a biosensor-based technique that is capable of identifying, measuring, and characterizing drug interactions with membrane-bound receptors, a protein family targeted by 50 percent of the world's drugs. Membrane receptors such as G-protein coupled receptors (GPCRs) are difficult to study because they require a lipid environment for native structure, each protein requires optimization, and only high affinity interactions can be measured. We use retrovirus pseudotype particles to present complex membrane proteins on a biosensor surface. We have developed a prototype of the technology, we have proven that it works, we have published the results in a top-tier scientific journal, and we are now extending its use to drug discovery. We have previously collaborated with several major pharmaceutical and biotechnology companies that have now expressed interest in the commercial use of the technology. The goal of our proposal is to: -Optimize conditions needed for efficient incorporation of GPCRs into retrovirus particles -Optimize conditions needed to produce large quantities of retrovirus particles -Explore the range of protein types that can be incorporated into retrovirus particles PROPOSED COMMERCIAL APPLICATIONS: GPCR proteins are the targets of over 50% of the drugs on the market today. Sales of drugs against membrane-embedded proteins in 1999 were over $60 billion and pharmaceutical research focussed on these proteins exceeded $12 billion and is growing by 15% per year. Membrane-bound receptors have been the most successful class of drug targets ever to be developed in the pharmaceutical industry, and our technology allows drugs to these targets to be developed faster and better.